Merge branch 'patch-1' into 'master'

Update rpi-resizerootfs

See merge request raspi-team/image-specs!17

rpi-resizerootfs

@@ -1,9 +1,7 @@
 #!/bin/sh
 
-roottmp=$(lsblk -l -o NAME,MOUNTPOINT | grep '/$')
+rootpart="$(findmnt -n -o SOURCE /)"
-rootpart=/dev/${roottmp%% */}
+rootdev="/dev/$(lsblk -no pkname "$rootpart")"
-rootdev=${rootpart%2}
-rootdev=${rootdev%p}
 
 flock $rootdev sfdisk -f $rootdev -N 2 <<EOF
 ,+